Diet data for Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), Atlantic halibut (Hippogloussus hippoglossus) and sea trout (Salmo trutta) from Porsangerfjord in Finnmark County, Norway, during 2009-2010. Cod were sampled from shallow water (file: Diet_G_morhua_Pors_shallow, average depth of 15 m) using fish rod and from deep water (file: Diet_G_morhua_Pors_deep, average depth of 180 m) using a shrimp trawl. Saithe(file Diet_P_virens_Pors.txt), haddock (file Diet_M_aeglefinus_Pors.txt) and Atlantic halibut (file Diet_H_hippoglossus_Pors.txt) were also sampled at deep water (average depth of 180 m) using shrimp trawl. Sea trout (file: Diet_S_trutta_Pors.txt) was sampled using gill nets at shallow water (2 m depth). The data was collected and analysed as part of the EPIGRAPH program. Proportions wet weight of various prey groups were estimated based on stomach analysis. The data is used in the publication: Pedersen, T., et al. (2018). Effects of the invasive red king crab on food web structure and ecosystem properties in an Atlantic fjord. Marine Ecology Progress Series 596: 13-31.